Interlocking system for railroads



.'hmz, 193s. y s NwlGHT 2,121,847

INTERLOCKING SYSTEM FOR RAILROADS FiledJuly 18, 1936 7 Sheets-Sheet 1 l 4ax 4MB 4 B Il -T`216 I ,47 W? l l i i i I `48 :256

I I 'f|"2ao 28a i 281 l i iJI- 9^ l I JE@ ,5- l *vl l 7 m64 ,261 l 26 [kees 11272 1.1??? INVENToR V BY 5' 7122 7 MONEY f JuneZS, 19.38. s, N W|GHT A I- 2,121,8474

,INTERLOCKING SYSTEM FOR RAILROADS Filed July 1 8, 193s '7 sheets-sheet 2 n Fla-.2'. n

INVE/NTOR June 28, 1938. s. N. wlGHT i l INTERLOCKING SYSTEM FOR RAILROADS Filed July 18, 1936 7 Sheets-Sheet 3 y FIGLS.

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gvslT/OR BY 4; ATTORNEY June 28, 1938. I s. N.w|GHT 2,121,847

INTRL-OCKING SYSTEM FOR RAILROADS Filed July 18, 1956 7 Sheets-Sheet 4 WMM ATTORN'EY yJune 28, 1938.

Filed July 18; 1936 7 Sheets-Sheet 5 mzn ATTORNY Junel 28, 1938.

i s. N. wlGHT INTERLO'CKING SYSTEM FOR RAILROADS Filed July 18, 1956 7 SheeLS-Sheel'l 5 mmm.

llNvl-:NTOR )L 'w ATTORNEY June 28, 1938. s. N. wlGHT INTERLOCKING SYSTEM FOR RAILROADS Filed July-'18, 193e 7 sheets-sheet ,7

lNvx-:NTC'R 5. ATTORNEY 'ETL Patented June 28, 1938 man IN'ilinlioCKINGV 2,121,347,vv l SYSTEM Fon nAILnoADs Sedgwick N. Wight, Rochester, N. Y.,assigncr,tov General Railway Signal Company,` Rochester,

-' ApplicationvJuly 178;- 1936, Serial No. 9,1;322 l This invention relates to interlocking systems for railroads, andinore particularly pertainsl to such an interlocking system infwhich a minia- Iture track layout in a control oflice has located #552 thereon the controlling buttons or levers for set'- ting up the desired routesthrough the actual track layout and in which the electric circuit connections between suchbuttons or levers ac-` Ycomplish the control of allr the various traffic mentof routes'through the track layout.

, The present invention relates toimprovements v in the interlocking systems disclosedin my prior applications Ser. No, 721,696, led `April 21, 1934' 'and Ser. No. 69,905 led March 20, 1936.

The organization of the system vembodying the present invention contemplates a miniature trackl layout located in thecentral .controloflice which corresponds to the actual tracklayout in the field andhas located thereon initiatingfand completing buttons for eachoi the-route determining points on the track layout. yInbther i words, for each signal location there is ,an initiating button, and for the end of each route there is a completion button. To establish a movement of trailic in a particular direction over a particular trackwayjroute, it isnecessary for the'operator to actuatethe initiating-button at the entrance to such desired route' andthen ,actuate the completion button for the exit `end of that route. U

This contemporaneous operation of an initiating button and acompletion button on'the miniature track diagram provides for the transmission irofvroute control codes over a multiple impulse code type communication system to `the i iield location so as to compositely operate all of` the track switches in such route to theirproper positions after which the 4signal for thatroute clears to allow the passage of traic over the route providing traffic conditions are safe lfor such passage. f f .l ,l It is also contemplated that .this system .will allow the control code for only one ofv several conflicting routes to be transmittedito-the 4iield location at any one time, so as to prevent any conflict of controls at the eld location. Y

In accordance with the present invention, the` preferred form of initiating or entrance button the completion or exit buttons-is of the selfrestoring push button type. The -system organization `then renders a cleared route whollyA de- 55: pendenty upon the manualrestoration of vonly the '3o claims! (orgie- 134) controlling devices 4employed for the establishis of the knob type which 'may be turned-to av particular position in which it remains; while,-

initiating or entrance button, the completion orl exit button having been only momentarily in an operated position.' l

The'entrance-exit methodof control ormanipulation so characterizes the system of the present invention, that it has'been aptly termed entrance-exit interlocking or abbreviated' as NX Interlocking.

Avide'sthat under certain emergency conditions codes may be transmitted so as to'individually operate the track switches in Vaccordance: Withthe positioning of, their respective emergency switch controlA levers, one for each trackswitch. This individual emergency control of the track switches is accomplished without the clearing of any, signal andwis so organized as to be pre-l vented'if such switches are included within` a cleared route.4 4 C Although, 'the present invention is more particularly directed to the features of such'an NXv interlocking systemk employing code communication between thel central office and the eld location, it"is to beunderstood that the various interlocking features involvedin the control of complicated track layouts, such as shown in my application Ser. No'. 69,905 filed March 20, 1936,

he system of the-present invention also'pro- 'l are to be understood 'as applicable tothe system v,

of the present invention.

Other objects,purpo'ses and characteristic features of the present invention Will be in part lobvious from the 'accompanyingjdrawings and in part pointed outas the description of the invention progresses. l, f 1

In describingthe invention in detail, reference will bey made to the accompanying drzniv-` ings, in .which like reference characters desig-` nate the same parts ,throughout the several Vi'ews and in which like4 letters in the reference characters designate similar functions or relationships with the ydistinctiveness' between such reference characters provided by the use of distinctive preceding numerals; in which likepreceding vnumerals in the reference characters, when applied to different letters, represent the inclusion of -such devices Vwithin-'a particular group; and in whichzl-r i y l Figs. 1, 2 and 3 when placedside by side illustrate the circuit arrangement employed in connection withthe system of the presentinvention for setting up theroute control codes lfor transmissionV 'over the multiple. `impulse type code rangement; by placing a large number of sheets' side by side, a simpliedmethodoffdisclosure"- has been employed wherein all of the control circuits for any one relay' are-shown in a coni-f tinuous relationship; while all" of the circuits which that relay may control are distributed between the several sheets of drawingsupon .which-r that relay is shown in block form.

For the purpose of further simpufying'tirenits;`

tration and facilitating in the explanation thereof, the conventional parts.andcircuitsconstituting the embodiment of the invention` have been shown diagrammatically and certain conventional illustrations have been employed, the-.drawings having been. made more with. the idea of making clear the purposeandlprinciples `of `the present invention together with its mode. of operation than with the ideaof illustrating. thespeciiic construction and arrangement of Apar-'ts Vthat would probably be employed. in practice. Y

The various relays and their contacts areillustrated in a conventionalY manner and symbols are employed to indicate connectionsv tothe terminals of batteries or other suitable sources oielectric current supply instead of showingall ofthe wiring connections to such terminals.`

The symbols (I) and are employedto indicate the positive and negative terminals respectively of suitable batteries or other sources of electric energy; and those' terminals with which these symbols are used are'presume'd to have current flowing Yfrom the V.positive terminal designated to the negative terminaldesignated y The symbols employed' with any one'loc'al cir'- cint are considered to designatethe' terminals'of the same battery or other suitable source, butas4 many separate sources may be provided as foundnecessary, or as many sources may becombined in a single source as found nece'ssary'orexpedient in the practice of the invention. If alternating' current is employed, then these'symbols 'should' be considered to represent the instantaneous relative polarities of the respective terminals;

Where groups of devices are'referred t'o in a general Way, such devices will be1 designatedby the letters or precedingV numerals characteristic of such group instead of citingpeach' specic reference character of that group.

Apparatus in general Track layout-Fig.' 7.-'-In the' accompanying drawings, the invention has been shown applied to a track layout including a stretchof double track connectedv by a cross-over TS; The' stretch of double track includes amain'lineextending from a signal I to a signal 2,- and another' main line extending from the signal 4 tothe signal 6. Signals 3 and 5 govern traic 'over' the cross-over TS between the two main line tracks;

Inasmuch as the opposite ends of a cross-over are usually operated at the same time', the'crossover is considered as a single track :switchTS andi iti is illustrated as operated by a single'switch.- machine SM, which may be of any suitable type, such for example as disclosed in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. However, two switch machines may be employed having either individual or collective control.

It should be understood that the invention is l not limited, as thus shown, to the control of the cross-over and signals of this chosen track layout, but may'be extended for any desired number of switches and signals and may be readily applied to all types of track layouts found in lnterlocking plants.

The signals I, 2, 3, 4, 5 and 6 are assumed to bef-color light signals giving the usual indications ofVgreen-for clear and red for danger or stop, and if an added' indication is desired, yellow for cautiom However, these signals may be of the search light type, semaphore type, or any otherv type of signal instead of the type chosen for the embodiment of the present invention.

The track layout illustrated in Fig. 7 has been shown as divided into'track circuit sections I4 and I5 by insulated joints indicated in the usual manner. These track sections are provided withl the usual track batteries and track relays of which only the trackl relays HIT and IST have been shown. These normally energized track circuits are wired in the usual manner to provide for fouling protection and to provide for the insulation of cross-overs and track switches, such details of wiring having been omitted for vthe sake of simplicity in the disclosure. These track circuits can of course be subdivided or lengthened as desired and arranged in accordance with any ofthe usual practices.

The track switch TS is shown as having associated therewith a switch position repeating relay WP. This relay is of the polar-neutral type and is energized with one polarity or the other in accordance with the normal and reverse locked positions ofthe cross-over TS and switch machine SM, and is deenergized whenever the cross-over TS is unlocked or is in operation. The polarized circuit for controlling such a switch repeating relay is governed through the medium. of a point detector contact mechanism as shown for example in the patent to C. S. Bushnell, Patent No. `1,517,236,'led November 25, 1924.

Control pand-In the central office, a control machine includes a control panel on which is located a track diagram correspondingto the actual track layout in the eld. This track diagram is shown as having a miniature cross-over ts'which is movable to normal or reverse positions by suitable electro-magnetic means in accordance with the position of a switch control relay Z.` A similar miniature track switch has been shown in detail in my prior application Ser. No. 431,748, filed February 27, 1930. i

On this control panel are entrance buttons NB' for each of the signal locations, so that entrance buttons INB, 2NB, 4NB, and BNB correspond respectively to the signal locations for signals I,2, 4 and 6L Also, an exit button XB is provided for the end of each route, shown as buttons I XB, ZXB, 4XB and GXB. It is to be understood that the ends of the routes may or may not correspond to the location of the exit buttons on the miniature track diagram, as a route is usually considered to extend from one particular signal to the next signal governing trac in the same direction, or to some arbitrarily chosen point.

Each entrance buttonNB is in the form of a knob which is rotatable from a normal position to a position where the index or the knobis in` invention. l ,Y

correspondencewith the indicator arrow onthe inside of the knob, and Vwhen. such entrancebutton is so positioned, its associated repeater relay,

NR is energized throughY circuits directly controlled by contacts operated :by the entrance buttonsNB, indicated .by dotted lines, and all of which has been shown in detail in my prior application Ser. No. 69,905, i'lledv March 20, 1936.

Within ,the entrancebut'tons NB are suitable signal indicators SK shown 4in Fig; 1 as indicators ISK, 2SK,; llSK and GSKLtf-"A particular indicator is illuminated when thesignal'at the'correspondingpsignal location is, cleared, all of whichY is accomplished through means not shownoin the present application for thelsake' of4 simplicity'and a 1 more ready understanding of the: present The exit buttons XB are of the .self-restoring push button type andf have been connected lto pushy button symbols byl'suitable dotted linesso as to make the relationship-readily apparent.

Y 1 Also, located on this` control 'signal are suitable trackindicators IATKIandIB'I'Kwhich are illuminated when the correspondingtrack sections, including track relaysfIEILan-diIST, are occupied. Inback'of the miniatureicrss-over switch points ts arersuitable .lockfindicators .LKA and LKB 4which are illuminated when the cross-over ts is Route 'reZays--Theffentrance ,button repeater relaysNR together .with tlresexitbutton XB con.- trol and select suitable route relays. These route included in a proposed route, aV cleared route, or

Arelays have been designatedlI-B for controlling trafiic'overthe mainftrackfrom signal ,il to sigrialv 'l'v in both directionsfrouteA relays 4--2 'for controlling trafc between thelsign'al 5 and the signal over the cross-fl inboth directions;A and route-relayI,-' '2,fo ontrollingtrafc between the signal v.I and thezsigfna'l 2 in,` `both directions. ,i l AThese Yroute relays suitably 'select circuits for controlling ythe switch controlrelay Z` to normal orfreverse positions in acx'rlance with `the 'partic'ular 'route' to be fsetgju'p andvf Aso forl closing suitable selections for determinlngthe route codes tobetransmitted. Thechangein positionof any route relay causes the initiation .of the code transmitter. 4Preference and .sequencebetween codesy l y starting button SB.V y

enforced by aA suitablelcode determining bank shownin Fig. 2 as including-change relays ICH, 2C`H-and 30H and code-determining relays ICD,

*ZCDmand 3CD.` Thechange ,relays C H arecontrolled by ,starting relays; SR, shown as relays Isn arid. 2SR.. kThe,chang'@naar SCH, is controlled by a manually operable self-restoring ,ifin' r:emergency switch. control,A lever :SML is shown in Fig. l asassociated 'withthe switch control relay Z for operatingv the s witch undery certain f emergency conditions to be` hereinafter VAThe `code determining; relays CDhave associated therewith a manually` operable self-restoring cancellingjbutton CNB, and alsosuitable relays such as relays CHR-CDS, C, FC, NC, PC, EP, SA, 2SA, IV, 2V, 3V,4V, 5V, 6V and LVlin order to accomplish the properfstarting ofthe code type'communication system andthe control of the code impulses on the line circuit interconnecting the centrall office with, the. 'eld station. The relays of Figs. 2 and 3 and their relationship tofeach other have beenshown in detail in the prior application of- Judge and Bushnell, Ser. No.V 640,062,11ed October 28,1931Uf -Y H InFig. 4 certain of the relays of Fig. 3 have their operatingl circuits shown, such as thestepping relays ,IV,2V, 3V, 4V, 5V, 6V and LV, together with the impulsing relay E and its repeating relay EP which causes the operation of the stepping relay bank and the impulsing of the control line.` circuit including line Wires I0 and I2 which eXtendLto they i'leld location. The current for' supplying impulses to the control line circuit 10 is derived from the control oflice battery CB and is applied in positive or negative impulses as selected bythe relays PC and NC respectively. y

The line relay F at the central ofce isrepeated bythe relays lFP and ZFP for each impulse; while the relays SA andA A2SA are picked up at the beginning of each cycle of operationand remain picked up-until the end of such cycle of i operation due to their slow action, although relay S'Ais only energized during the impulse periods.

The stepping relays V-have associated therewith a half-step relay VP.

The line wiresl I0 and I2 extend to the field locations each of which has a code receiving `apparatus as shown yin Fig. 5, it being understood `that thenother eld locations havesimilar apparatus. But it is deemed sufficient for an understanding of the -present invention to conv Sider the operation .with respect to only a single location. i A line relay F1 of the three position polarized type repeats the polarity of each of the impulses impressed upon the line' circuit. Each impulse irrespective of its polarity, is repeated by the line repeating relay .FP1 so longasthis iield location is in operation. The relays SAl and SB1 are picked up at lthe beginning of a cycle of operation and are dropped outat` the end of a cycle of operation. Y v A bank of vstepping relays IVI, ZV1, 3V?,` IVR 5V1, -IVl and LV1 operatev one step for each of the time spaces between the impulses impressed i upon the line circuit including the line wires Il)` and I2, while the half-step relay position for each impulse. i

At the beginning of the cycle of operation, the firstgroup of impulses determines the selection or the station and is registered on the station selecing relays SO1 and SOS'lv; while the latter part/of the series of impulses isy registered on positive and negative code receiving relays PS andr NS'.

The positiveand negative code receiving-relays PS and NS have been shown in Fig. 6 as including relays 4PS,'4NS, 5PS, 5NS, SPS, GNS, ,'IPSv VPl changes its' and TNS, which relays in turn lcontrol the route relay I-2R, but during certain emergency control conditions, as hereinafter described, the relays WN and WR are directly controlled by lcode combinations .set up on the relays PS and NS.' l The route relays, such as relay I-2R, coop-v erate with ,the switch position repeating 'relay WP to select circuits for the control of signal relays IG, 2G, 3G, 4G, 5G and' 6G which ,respectively cause their signals I, .2, 3, 4, 5 andi to the field stations.

to indicate stop when such` relays Gare deenergized and to indicatel clear when the respective relays are energized, all in accordance with the usual practices.

Communication part of the .s;1,lsz'm`.-ItV is' to be understood in connection with the communication part oi the system shown in Figs. 2, 3, 4, 5 and 6 that reference should be made to the prior application of Judge and Bushnell, Ser.' No. 640,062, filed October 28, 1932, for an exhaustive description of such a code type` communication system, only that part of such description being pointed out herein as is deemed necessary for an understanding of the present invention. For convenience in comparing the parts of the present disclosure corresponding to the' parts of such prior application, the same reference characters have been employed in this disclosure as were used in such prior application.

Although the present invention is contemplated as employed in connection with al communication system providing both `for thel transmission of controls from a central control oi'ce to any one of a plurality of field stations, and for the transmission oi indications from each oi` the field st'ations to the control ofce, as in the above mentioned application, Ser. No. 640,062, the present invention relates-more particularly to the trans` mission of route controls from the central oflic Thus, only those parts of the communication system relating more directly to the transmission oi controls have been in'di-` cated; and similarly, the description relative to the features of the communication system' will be directed more particularly to the transmission of controls. i

For the transmission oi controls, a transmitting equipment is located in the control ofce and a receiving equipment is located at each ofthe various field stations. These receiving equipments are connectedrto the transmitting equipment in the control oiiice by a suitable stepping and con# trol line circuit comprising a stepping line wire I0 and a return line wire I2.

The stepping line wire I0 includes athree; position biased-to-neutral polar line relay FH at thecontrol oce and at each of the field stations. The transmitting apparatus at the control' oice energizes the stepping and controlline' circuit with a series of time-spaced impulses of polarities selected in accordance with the station code calls and the route control codes to be transmitted.

Each series of time-spaced impulses .comprisesspace periods, which is conveniently termed an` operating cycle. In the beginning of such an operating cycle7 a slow acting relay SA in the central ooe (see Fig. 4) and a similar relay S-A1 at each iield station (see Fig. 5) is energized. These relays SA are made suiicientlyv slow acting to be maintained picked up between successive impulses throughout the operating cycle, `althougl'i'their circuits are momentarily opened during each time space period.

The application of the successive impulses of a cycle to the stepping circuit causes the oper-' ation of the stepping relays V at the control omce in synchronism with the stepping relays at each field station, one step for each time space between impulses while the polarity of the impulses serves to select a particular eld station and to selectively position the relays PS and NS at the selected station.

As the station selecting part of an operating cycle is completely disclosedv in the above-mentioned application Ser. No. 640,062, only the control part of the operating cycle will be discussed in detail although the station selecting part of station to cause the stepping operation to cease l at that station when such station fails to be selected during the station selecting part of the op'- erating cycle.

Keeping in mind this general organization of the completeI communication system contemplated in connection with the particular embodiment of the invention illustrated, and particularly that station code calls are transmitted for the selection of a particular station from among a plurality of'such eld stations, after whicha route control code is transmitted to the particular selected station to control the traffic governing devicev at such station, consideration may now be given to an explanation of the manner in which the codes are set up in the central oice and transmitted to the field station to accomplish the setting up of a route through the track layout.

' Operation The system is normally at rest, but may be initiated by the operator for the transmission of controls, as hereinafter explained. While the system is in thiscondition of rest, or in the pe` riod of blank as Vsuch `condition is sometimes termed, the stepping and control liner circuit is normally deenergized; and similarly, the major part of the relays of the system are deenergized. 'Ihose relays which `are normally energized will have their circuits pointed out when their operation and functions are described.

Although the cross-over TS (see Fig. '7) is usually left inv its last operated position, it has been shown in a position for the passage of main line trafc. The signals are normally at stop as the signals are illustrated as being of the colorlight type, and it is to be understood that the lower or red indicator of each signal is normally illuminated.

With the track sections I4 and I5 unoccupied the track relays IAT and I5T are of course normally pickedup.

Referring to Fig. 1, all of the entrance buttons are in their normal positions, so that the system is ready to provide for the establishment and clearing of any of the possible routes through the track layout.

Entrance-exit route interlocking-As above mentioned, the system of the present invention is of the entrance-exit type so that if the operator desires to set lup a route from the signal I to the signal 2, he rotates the entrance button INB 90 in a clockwise direction, which closes suitable contacts to energize its repeating relay INR', and

in which position the entrance button INB remains until manually restored to put the route to stop, as later described.

After actuating the entrance button IN'B, the operator then glances along'the miniature trackway and iinds that there are no lock lamps illuminated betweensuch entrance button INB and amiga-i7? theexit button ZXIB which designates-the end of the route and which the' operator depresses. In some cases the lock lamp LKB might be ileluminated, such as when a route is cleared from the signal 4 to the signal 6, as described in my above-mentioned application'Ser. No. 69,905, but

under' such circumstances', they miniature crossover ts would indicatethel cross-over TS-to 'be in a normal position, so that its operation would not be required to set up the route fromthesi'g-t` nal I to the signal 2, thereby making it perfectly' proper for the operator to actuate the` exitbut- The operation of the exit button 2X3 occurring contemporaneously with the entrance button l2NB in an operated position,` closes a pick-iup circuit for route relay |-2`from (-1-), through a circuitlincluding front contact 20|l-of vrelay INR;` back #contact 20| of route relay '4-2, windings of:A route relay |-2, back contact 202 of .entrance relayf 2NR,..backpointof exit ybutton* i2XB, to 'Ihe energy. which iows inthis circuit causes theroute relay |-2 to actuate'its Vpolar contacts tothe right and to pick up :its neutral contacts closing its stick circuit, which allows the operator to 'releaser the self-restoring exit button 2KB, by reason of the application ofnegative' potential from (L), vthroughv front `contact-m3 of route relay |-2, polar' contact 204 of route relayy |'-.2 in :aright-hand position, tothe Frighthand terminal ofrelay I-2. i

Each of the route relays are picked..l up in a similar manner and are maintainedfstuck up d ependent upon the return of theirrespective en'- routes established at thesametime, the Apick-11p y. circuit for the route relayfd-B does not :include aninterlocking contact on the route relay |2,

nor does the pick-up circuit for route relay |-2 includeaback contact-on ,routev relay 4 6'.; -Itis believed that the remaining features of interlock between entranceexit route buttons will be read-v ily-*apparent from the; drawings, it beingunde'rstood that only onejroute relay vfromamongfa plurality of route relays for conicting routesmay be picked up at `,any one time.;` v Y `..*Igzdezrlo'clc for non-conflicting route codes.- Eromthe `above discussion of. the communica-Y tionsystem, it will be understood thatonly one code combination can be transmitted vover the relay, such as relay ,4-16,.,t'o` transmit a distinctive 65, code -to'the field location for establishing'a."'route4 I d route'relay could be-picked up at a timeby 'reason-'l communication system-during any one" cycle of; operationandas-it is necessary foreach Irollte the systemis soorganize'dthat only'fone-route relaycan be effective-to condition the codesend-'a ing relays of theA communication systemj'duringi anyoneycycley of operation. If `all of :the froute relays `Were for conflicting routes, then only one'` offthe route interlocking abovei'de'scribedVso that"l a ffurther interlock` between the codes for the'differentroutes would ,beunnecessary y 1; ,I-IoWever; the usual interlocking plant hasmany.-y

different groups ofv` 'conflicting' routes, each of which" provides for aso-called parallel'route. In other words, everyfinterlocking plant usually has aflargenumber of parallel routes, that is, routes which-maybe set up atthe same time and donot conict, each parallel route of which has asso ciated therewith routes which conflict Withsuch parallel route. Therefore, a parallel route and itsconflicting'routes-.may be conveniently termed a group ofconicting routes.

' -fAs each group of routes may have a route relay pickediup at any time, irrespective ofthe condi of fthe interlocking1plant, the system ofthe present invention provides an interlock between these groups solthat-onlyone ro,ute' relay, althoughv several -may. be simultaneously picked uitwill be capable-of conditioning the code transmitting meansduringvany particular cycle ofoperation. T! The present disclosure shows onlya single cross-overfthat'providesY a route which is conflicttions ofthe route relays for the remaining groups ing ywith both ofxthe two -parallel routes, but it is tobeeunderstood-thatthe'association ofthe paral-` lelfroutes'with'iother routesv may be accomplished 4 inthe usual Way. yEven though only av singleeld 25 stationfisiusedwfor the control lof, lthe cross-over it Aisznecessary to Iprovide'an interlock between the parallel routes inthepresent disclosure because both-"ofthe routel relays 4-6 and |-2"may. be

picked'upatthe same time. .l f

For the' purpose'of'providing an'interlock-beytween different groups-of routes (and other purposes'flater .to bepointed out) a 'code determiningv bank of relays is provided y(s'e'e Fig. 2).

achange relay CHV and a code determiningrelay v d In this bankfeach route' group has associated therewith CD; The relay CH is picked up whenever a route relay' in alparticular `route group Ychanges its position, `andremains picked up until theucode condition -establishedby the' change in vposition of thai-route relay has been transmitted over the` communication system. vrThe Ycode determining relay ,GD associatedwith suchchange relay is picked -up by therv relay CH, when the ypredetermined orderfof v,transmission ybetween the groups permits-thetransmission of a code for that group. Infiothenwords,the relaysV CD for the several groups tare so interlocked that only one Vof these"` relaysprnay-v loe-picked up during any particular operating cycleof the communication system'and theserrelays are picked upon the successive cycles of; operation in a predetermined order as determinedlby the interlocking circuits.

Under certain emergency conditions:` hereinafter; discussed, it becomes necessaryto individuallyifoperate the 4track switches andA cross-overs, v'soa-that this. code determining bank' includes .a

change relay' vCI-'I and -a code determining relay C D foryeach group of track switches which mayv beindividuallycontrolled on vparticular operat-` Itzis to be understood that if .therefwere more routegroups inthe track layout, that each route group would have its additional relay CH and CD connected to th bank'in asimilar manner asv thosershcwmalthough such groups might be controlledthroughthesam'efor another field station. v

Also;y whenA seyealfeld stations are employed,k ealiwstation 'has its relay CH and CDV for the',

routeegroupsA associatedfwith such station and theygarefincluded inthe code'determining bank 'of Fig. v2 with the same kindv ofan interlock as showrifforthe relays ICH, 20H, 3CH,v ICD, 2CD and-130D. 1

@Regardless-of? the number of stations, and the ifo groups of routes for such stations, `a cancelling button CNB provides `that any changeV which has been stored in the code determiningzhank may be manually cancelled, so that the operatorf.,rnay

. set up an entirely new set ofcontrol conditions.

- Initiation of the system.-:We may now con-- sider hcw the picking up of a route relay,.such as route relay l-2, effects the storage of Va change in its associated relay `2CH so as to .accomplish the transmission of a route control code. 1 u

The relay ZSR is normally energized by .a circuit closed from through a circuit including back contact 205 ofroute relay I-2, lower winding of relay ESR, front contact 206 .of relay 2SR,

When the route relay I- 2 is picked up, as

above described, the opening Aor AVback contact 205 opens the energizing circuit for the lower Winding relay 2SR, and closes .an energizing v circuit for its upper winding from (fl-i), through acircuit including front contact 205,` upper winding of relayv 2SR, front contact. 206 of relay 2SR, to ,providing .that the relay 2SR is not already dropped away dueto its momentary deenergiza.- tion' between the opening of back contactv205. and the closure of `front1 contact1205. I If current flows in the upper winding of relay.2SRit reverses the magnetism in the relay 2SR which causesv such magnetism to pass through zero, because the upper and lower windings are differentially connected as indicated bythe arrows within their windings. Thus, the relay quickly drops away and remains dropped away as both circuits are now open at iront Contact .206. v

The dropping Yaway of the relay `ZSRscloses a pick-up circuit for the change relay 2CH Vfrom through a circuit including vback contact 20l of relay ZSR, wire 208, winding of relay 2CH,` front contact of cancelling button Cl\lB,*to The current Vv'vhi'ch flows in, this'circuit .causes the relay 2CH to immediately pick up and close a stick circuit from"(+), through `a circuit in-1 cluding back contact 209 of relay i2CD,front con'- tact 240 of relay 2CH, windings'of .relay2CH,'

front contact of cancelling button CNB, to As soon as the change relay 2CH picks up,it

also closes a circuit for restoring the relay -ZSR. from `(l-), through a circuit-includingfront-contact 205 of route relay I `2,"upper winding ofv relay 2SR, wire 2H, front contact 2I-2 of relay 20H, to When the relay ZSR pi cks"up, the closure of its front contact 206 connects to the right-hand terminal of its upper vwinding thereby closing its stick circuit to maintain the relay ZSR picked up irrespective of the subse` quent opening of contact 2I2 of relay 20H'. The' opening of back contact 201 of relay rZSIf-ref-V moves the (i-) from the pick-up circuit of =the relay ZCH, but the rel'ayZCI-I remains picked up by reason of. its stick circuit, above pointed out.

It will be readily apparent that the shift of the contact 205 from a front point to a back point will cause the'drop away "of the relay 2SR in `a .similar manner as` the shift from the back point to the front point, which deenergizaton of` the relay ZSR will in turn cause the .picking Vup f the relay 2CH and .its .own restoration. In, other words, the relay ZSR-,is` dropped away toA pick up the relay` H and isgagain :restorede'by thepicking up of the relayy 2CH.regardless of whether the route relay. I-v-2 is' .pickedy up. or whether it is dropped away.` l

. The relay ISR is providedwithanormally-'en-A ergized holding circuit closed from through 7,5;*a circuit includingbac'kecpntact 2113.0ffi1011te rlelay A+6,. back contact. .2.-I lief route relay .4 2, lower*..winding,of ,relay ISR, `front contact 2|.5 of! relay :iS-R, lto"(. ent thatfthe picking up of leither .the route relay 4.-;-6 ycrut/he lrouterelay :4 2, only .one .of whichcan bef'picke'doupfat the same time, shifts theiapplication refill-)to the upper winding of relay'lSR byzeitherthe closure of front contact 213,.,or therront contact 2| 4 .ofthese two route relays respectively,. so that..the relay ISR. will` back lcontaotz23 ofrelay ICD, front contact f24 of' relayliCH, windings of relay ICH, front point Vof cancelling buttonl CNB, to

.:The pickingup .of relay ICH .completes a re.- storing: circuit :for the :relay ISR .by applying ),v--throughyfrorit `contact 2I.8 and wire 2I9- tofthe-.rightfhand terminal .of relay ISR, which is'completed pwith route` relays .4.-6 and 4- 2 either iboth :deenergized ,or .one or :the other -picked up;H ,l l In the event .'.that the operator desires to-transmit a switch control code inaccordance with` the position oizrthewlever SML,.as later described, he mustgde'press .the .self-restoring starting button SB to'close .a pick-,up circuit for the relay 3CH from..(,l through a` circuit including` a back contact of starting button SB, wire 220, windings of relay i3CH, iront contact of cancellingcbutton CNHEto (1 The `picking up of the relay v3CH closesyi-ts `stick circuit from through [a circuit including back contact "|52 of relay 3CD, front-.contact ,Ii5l.ofrelay.3CH, `windings .of relaylSCH, iront contact of cancelling button CNB, to' Y j .I-f `sei/'eral iofthe change relays CH are energized at the same time, only one of the codedeterminingrela-ys CD can `be picked `up during a cycle u of operation ofv the communication lsystems",.-=which will lprobably be best understood after auco'nsideration of the manner in which a particular@ code determining relayCD is picked up when only one relay CH has been conditioned. "'llAssu/ming that'the'operator desires to vset up therouteirom the' signal vI to the signal 2, as above'lc'onsidered, the r`pickingup of the route relay-1 2 causes Athe dropping ofthe relay ZSR followed 'by-the picking up of the relay ZCH which in turn restores -therelay qvZSR..

The picking-up of the relay 2CH `also supplies' energy to the change repeating relay CHP by a circuit closed from through a circuit including back contact 25 of relay SA, back contact26of relay FC, upper winding of relay CHP, wire223, frontcontact 224 of relay 2CH, to As'soon as the relay CHP picks up, it is energized through its stick circuit from throughA a circuit `includingloack contact `30 of relay LV, iront contact 3| of relay CHP, lower winding of relay CHP, to

VThe picking! up of relay CHP closes front contact 63 so as tosupply energy from to the heel Vof contact 64 of relay EP so'that although the-contact: 64 -is intermittently opened throughoutlthe cycle .of operation, the relays 2CD and CDS remain Ienergized until the relay CHP is dropped away Lupon .theiopening of contact 30 it will .be readily apparfill.'

4lso

at the end of the cyle of operation when thel la'st step relay LV is picked up. It will be noted that the relay CHP could not be picked up if the system Were in operation because of `the open condition of back contact 25 of relay SA', nor could has been disclosed in the above-mentioned ap-` plication'Ser. No. 640,062.

The picking up of the relay CHP closes .its front contact 2!) which completes a. pick-up circuit for the control oce starting relay C from through a circuit including back Contact '28,01* relay SA, front Contact 29 of relay CHP, windings of relay C, to `As soonas the relay C picks up, it closes its stick circuit from l (-I-), through a circuit including back-contact 32 of relay 2SA, front contact 33 of ,relay C, windings of relay C, to I:

At the start of the cycleof operation, the relay SA picks up first followed by its repeater 2SA so that front Contact 28 is closed before back contact 32 opens, thereby maintaining the stick circuit for the relay C throughout the cycle of operation.. But at the end of the cycle of operation,` the Yrelay SA drops away before its repeater relay 2SA drops thereby opening front contact28 before back contact 32 closes so that the stick circuit for the relay C is momentarily opened and therelay drops away.

. The pickingy up of the relay C completesa pickup circuit for the relay 2CD by the closure of its front contact 35, which pick-up circuit isclosed lfrom through a circuit including back contact 30 of relay LV, front contact 35 of relay C, back contact 34 of relay 2SA, back contact 36` of relay CDS, back contact 31 of relay` 3CH, front contact 38 of relay 2CH, upper winding of relay 2CD, front contact of cancelling button CNB, to

As soon as. the relay `2CD picks up, its stick circuit is closed from (-I-) through a circuit'including back contact 64 of impulse repeating relay EP, windings of relay CDS, front contact 22| of relay 2CD, lower winding of relay 2CD, front contact of cancelling button CNB, to The current which flows in this stick circuit notA only holdsthe relay` 2CD energized, but also picks up the code determining stick relay CDS which opens its back contact 36 to prevent any other relay CH (which is more superior to the'relay'ZCI-I) from picking up its relay CD, such as for example, the relay 3CD' by the relay 3CH closing its front contact 31. It is of course apparent that the opening of back contact 38 of relay 2CH prevents an inferior change relay CH from picking up its relay CD.

The picking up of the relay 2CD shifts the sup ply of energy for the stick circuit of relay 2CH from (-I-) ,through back contact 209 of the'makebefore-break contact 209, to a circuit closed from through a circuit including back contact 66 ofvstepping relay 6V, wire 222, front contact 209 of relay 2CD, front contact 210 of relay 2CH,l

windings of relay 2CH, front contact of cancelling button CNB, to This stick circuit for the relay 2CH remains closed until the system-.operates througha cycle opening the back contact 66 on the sixth step of the cycle. This releases the relay 2CH in which condition it remains until a subsequent change is registered on the storing relay 2SR. Thus, withthe relays 2CDand C both pickedup, the system is conditioned. totransmit impulses for a cycle 'of operation." However, itis considered expedient to briefly consider thestepby-step operation in the central oice withwrespect to Fig. 4 before considering how thek distinctive characters of the impulses are `selected in accordance with the codes to be transmitted.

With the relay C and CD both picked up, al pickup'circuit is closed for'one or the other of the relays PC or NC, as will be presently described, but considering for the moment that one. of these relays is picked up without going into the'detail ofits manner of control, it will be apparentthat a positive or negative impulse is placed upon the control line circuit includingl .the line wires l0 and I2.

V-If the relay PC is picked upvthe control oiiice battery is connected into the line circuit toV transmit 'a positive impulse; 4While if the relayl NC. 'is picked up the control oilice battery CB is connected into the circuit so as to transmit a negative impulse. `YIhe'application of an impulse upon the stepping and control line circuit energizes the line relays F in accordance with the particular polarity, but irrespective of the polarity'of such impulse the line repeating relays FP are energized to repeat the impulse. i'

In 'the central oce, the closure of front contact 68 of relay FP energizes its repeatingv relay 2FP which in turn through contact 69 energizes relay SA, which is also repeated upon the closure of its contact 10 by relay 2SA. I

As soon as the relay SA picks up a circuit is closed for picking up the half-step relay VPfrom (-l-) through a circuit including front contactfll of relay SA, front contact 12 of relay 2FP,.` back contact 13 of relay IV, windings:v of relay VP, to As soon as the relay VP picks up, it closes one of its stick circuits from (i-), through` acircuit including front contact 1I of relay SA, iront contact 14 of relay VP, back contact-13 ofv relay IV, windings of relay VP, to

With the relay VP picked up, a pick-up circuit is closed for the relay E as soon as relay 2SA has picked up from through a circuit including front contact of relay 2SA, front contact 92 of relay VP, back contact 93 of relay IV, upper winding of relay E, to v The relay E closes front contact 95 `and energizes its repeating relay EP Which in vturn opens back contact 52 included in the stepping and Lcontrol line circuit causing the end of, the first impulse period. I

Therefore, it is apparent that the durationlof the rst impulse includes the successive pick-up periods of the relays F, FP, ZFP, SA, 2SA, E and EP. f

The deenergization of the stepping and control line-circuit is repeated by the relays F, FP and 2FP, but the relay SA andZSA, being slow acting, remain picked up during the time space periods between impulsesso4 -that they remain steadily picked up throughout the cycle of operation.`

, When the relay 2FP `drops away, a pick-up circuitk is closed forthe stepping relay IV from (-1-) through a circuit including front contact 15 4ofrelay SA, back contact 16 of relay 2FP, front up` and stick circuits previouslycpointed out for therelay VP, but another holding `circuit ihas been closed prior to the vpicking ,up of `the relay IVby the closure of back contact I2 of relay-ZEP so that .the relay VP remains picked :upiby reason of a stick circuit from (-l-), through .a circuit in.- cluding front contact II of relay SA, back contact 1210i relay 2FP, front contact .80 of relay VP, windings of vrelay VP, to This holdingicircuit provides that vthe relay VP is held up until the `relay 2FP is again picked up.

lThe picking up of relay IV opens `back contact 93 lwhich deenergizes the relay E, which in turn deenergizes :the relay EP by opening contact95. As soon as the relay EP drops away, the contact 52 in the line circuit is closed so that the next impulse is impressed upon the line circuit the character ,of which is determined by the particular pulsing relay -PC or NC which has been picked upwduring xthe-timethat the relay EP has maintained the line circuit open.

Therefore, it will be apparent that the duration of vthe time space period vincludes the drop away periodsxof `the relays F, FP, 2FP, E and EP asvwell as the ,pick `up Yperiod of the proper stepping relay, in this case vstepping relay IV.

The application of the second impulse upon the line circuit causes `the energization of the relay F at the control oice and at each field station which repeats the polarity of the impulse. However, lirrespective of the polarity of the impulse the relay FP in the central office and the relay 2FP -are ,successively picked up. As soon as the relay 2FP picks up, the relay VP drops away .by reason .of the opening of its :stick circuit including back .contact 12.

Upon the dropping away of the relay VP, the next energizing circuit for the relay E is closed from through a circuit including front contact 99 of relay 2SA, back contact 92 of relay VP, back contact 96 of relay 2V, front contact 91 of relay IV, lower Winding of relay E, to energization of lthe relay E is repeated by the relay EP which marks the ,end of the second impulse by the opening of back contact 52. Therefore, it will be apparent that the second impulse `is of a duration which includes the pick up periods of the relays F, FP, ZEP, `E and EP as well as the drop-away period of the relay VP. All of vthe subsequent impulses are of the same duration, while all of the 'time spaces are similarly of the same duration as described vin connection with the rst time space period. The rst -im pulse period is the longest impulse i-n the cycle for the purpose .of picking up the cycle marking relays SA land12SA in the central oflice and corresponding relays at the field stations, such` as relays fSAl and SBl of Fig. 5.

It isbelieved that it will be readily apparent how the step-by-step operation continues throughout Vthe cycle of operation, a stepping relay being picked up upon each dropping away' of the relay 2FP and the relay VP changing its position upon each picking up of the relay 2FP. Y

During the last impulse of the cycle of operation, the VP relay is picked up, which closes a pick-,up circuit for the relay LV as the stepping relay 6V was picked up upon the preceding ltime space period. This circuit is `closed vfrom through a circuit including front contact `.88 of relay VP, jumper 225, front contact 89 of relay 6V, windings of relay LV, to As soonas the relay LV :picks up, its stick circuitis closed vfrom (flthrough ,a ,circuitincluding Vfrontcontact 99:ofo'relayL/2SA, front contact 9| 'of relay 'LV, Winding-stof ',relay LV, to

- zlt =is ,noted that the jumper 225 provides for the :closure ofthe pickup circuit of relay LV uporrfthe 'picking up.of relay VP. This is true When theV steppingrelays IV, 2V,3V, etc. are an even number, as;,in this disclosure. However, if an odd number of stepping relays V were employed, the jumper 225 would be in its lower position so asjstoV include the back contact 88 of relay VP instead of front contact 88.

.itfwill -beapparent that relay LV is stuck up upongfront contact 99 of relay 2SA, which is the lastlslowv acting cycle demarking relay to drop awayat therendof the cycle, therefore rendering the relay LV the last relay in the system to restore to normal.

tIlhe .picking vup' of the relay VP with the step- -pinglrelayV picked .up closes an energizing circuit forithe relay E, lfrom (-1-), through a circuit including front contact '90 of relay 2SA, front Contact 92 of relay VP, front contact 226 of relay 6V, upper winding of the relay E, to This energization of the relay E is repeated by the relay EP upon the `closure of front contact 95, which.relay.EP in turn opens the line circuit at back contact 52 marking the end of `the last impulse of the cycle of operation. The relay EP is maintained energized by reason of the maintained-energization of the relay E, even upon the dropping away rof the relay VP when the relay SA drops for the end of the cycle, by reasonof `an energizing circuit closed from through a circuit including front contact 96 of relay 2SA, back contact 92 of relay VP, front contact IDB of relay LV, lower winding of relay to Having 'considered how the step-'by-step operation V.takes place so asto impress impulses upon the Aline circuit, we may now consider how the distinctive .characters of these impulses are selected in accordance with the codes to be transmitted. f

Transmission of station .and route codes- As above mentioned, `the system of the present/invention is contemplated as being-used with a communication system having a large number of afield stations, although only one has been shown in the present disclosure, the remaining stations ibeing similar to the one shown. Thus, the first part of an operating vcycle must 'have' impulses of `polarities selected in accordance with the c ode call ofthe station to which the route codeV is to 'be transmitted, while the later for remainingimpulses of the cycle of 4operation must have their polarities selected in accordance with the particular route code then set up for that station.

`For convenience in considering the various codes which are used in the present disclosure and` for the various possible codes which may be set uDfa typical code table has bee-n shown loe-` low. This typical code table shows all of vthe route control codes which are employed at the station shown in Figs. .5, 6 and 7, but-.preceding these Vroute `control codes only that station select-- ing code required for the station under .consideration has been shown.- The first three impulses oia cycle are shown as used for station selection purposes;` While the last four impulses are shown as used `for route control codes. When the 'three impulses `lfor station selection are combined in the `rdiieren-t possible combinations according tothe-exponential law fof the Baudot codeeight distinctive `station `code calls are provided. ,For each :ofzzthesefstation codes, 4sixteen route control codes are provided by the four vcontrol impulses.

Thereforevif the full code capacity of the seven 1 impulse cycler were employed,` the code table would haver 128 codes, but for the sake of simplicity only the codes employed at the station shown have been included in the typical code table. f

Typical code table Route control codes station selection Code No. v

- With reference to Fig. 2.the `code determining Y relay ICD is provided with station selecting code jumpers 221, 223 and 229; code determining relay 2CD is provided with static-n selecting code J jumpers 23?, 23H and 232; and, the code determining relay 3CD is provided with station selecting code jumpers 233, 234 and 235. v

The relays ICD and 3CD are respectively provided with control code jumpers 236 and 231. v

The relays PC and NC have their right-hand terminals connected toy While their leithand terminals are connected to buses 41 and 48' which extend through the code determining bank o-f Fig. 2 and the route relays orA Fig. 1 yas well as the Z relays associated with the` emerk gency switch control levers, such as lever SML.

Upon the picking up of the cycle controlling 1 relay C and the particular codedetermining reylay CD up for the cycle of operation to ensue', the circuit selections-are conditioned so that the i station selecting code jumpers for the relay CD which is picked up are' successively rendered effective tol energize therelays PC and NC for the successive impulses after which the connections on the-.route relays, or the Z relays are .lays 4PC 'and NC for the remaining successive imsuccessively rendered eiective to position the-repulses of the cycle'of operation. It is believed that this functioning of the system will be readily understood by a consideration of the manner in which the station selecting code is impressed upon the line circuit bythe code jumpers 230,

23| and 232 of the code determining relay 2CD and by the connections associated with the route relay |-2 assuming such relay to be picked up to clear a route from the signal VI to the signal 2.l

contact 24| of relay 3V, back contact 242 of relay 2V, back contact 243 of relay IV, code bus 244, front contact 245 of relayv2CD, code jumper Y 230, bus wire 41, windings of relay PC, to

- impulse applied to the line circuit to be positive,`

negative by energizing the relay NC `over the relay PC over the bus 41.

This impresses a positive impulse upon the line circuit for the rstimpulse period. By referring tothe typical code table, it will be apparent that this agrees with the character of the impulse for the first impulse for station selection.

Uponthe picking up'of the relayfIV during `the rst time space period of the cycle, contact 243 shifts the applicatio'nfof energy to the code bus 246, whichthrough front contact 241' of relay 2CD allows the code jumper 23I" to 'cle-l termine thatY the next impulse appliedto ythe line circuit shall be positive by energizing the relay PC over `the bus 41.

Upon the picking up of the relay 2V during the second time space period of the cycleLcon-ytact-242 shifts :the application of energy to the code bus 248 which through fro-nt contact* 249 of relay 2CD allows thecode jumper 232 to determine that the next impulseapplied to the line Vcircuit shallv be negativeby energizing' the relay@ NC over the bus 48. y The route lrelayy I-2 now determines the character of the remaining impulses ofthe cycle. As

`the route desired to be set up is from the signal I to theY signal `2,'the route code employed is the code No. 3 in the typical code table,` from which table, it wiu be apparent that the rfoliowi ing description of the successive circuitsl set a upon each of the steps will select the code charia; q

acters for this code No.3. l i Upon the picking up of. the relay 3V during the third time space period ofthe cycle, convtact 24| shifts'the application of energy to the code bus 259 Whichthrough front contact 254 of relay 2CD over the wire 258 and through front; Vcontact 262 of route relay I-2 causes the fourth impulse applied to the line circuit to be `positive by energizing the relay PC over the bus 41.

Upon the picking .up of the relay 4V during` the fourth time space periodr ofthe cycle, conaz'.

tact'24 shifts the application of energy to the,A

code bus 25| Which through front contact 255 of relay 2CD over the wire 259` and through-front contact263 of route relay I-2 causes the fifth by energizing the relay PC overthe bus 4-1.

Upon the' picking up ofthe relay 5V during the fifth time vspace period of the cycle, conf tact 239 shifts the application of energy to the code bus 252, which through front contact 255:

of relay 2CD- over the Wire 26B and through' front contact 264 of lroute relay I-2 causes the sixth impulse applied tothe line circuit to be bus 48. l

55 I Upon the picking up ofthe relay 6V during" the sixth time space period fof. the cycle, con,

tact 238 shifts the application of energy tothe code bus 253 which through front contact 2510i relay 2CD over the wire 25| and through front,l

contact 255 of route relay I`2 and polar contact265 of route relay I'-2 in a..righthand position causes the seventh impulse applied' to the line circuit to be positive by energizing the Thus, the route relay I-2 accomplishes thev transmission of the code No. 3 forv clearing; a route from the signal l tothe signal 2.y

We might consider at this time that the operator after having cleared this .route desires,r

to putl the route to stop either'because of a change in his plans for ltheon-coming train or because the train has passed over .the route and he desires to change the route setup for a A.succeeding train. To do this, al1 that isneces?.Y

` causes the picking up of the relays H and 2CD j code to 'differ for the two complete codes.

and suitable circuit connections.

providing the operating conditions of the communication system are proper, as previously de-V scribed for the transmission of a clear code, so

jthat a code is transmitted with the contacts of the route relay I 2 deenergized.

vWith reference to the typical code table, the stop code has been selectedas code No. 13 so that the back contacts 262, 263, 254 and 265 of the route relay I 2 are so connected to the buses 41and 48 as to provide this code No. 13. In this connection it might be well to know that the clearing code No. 3 is in the first half of the Yroute control codes while the stop code is in the last half, which causes the fourth impulse in the This makes necessary the wire connection from the heel of contact 254 of relay 2CD through wire 258 and contact 262 of the route relay I 2 to the buses 41 and 48. But, if two codes were employed in the same half of the route control codes, such selection might be eliminated and a yjumper connected from the heel of contact 254 to one or the other of the buses 41 and 48, similarly as for a station code jumper. This has been illustrated specifically in connection with the route codes for the route relays 4 2 and 4 6 by the provision of the route control jumper 236. These two methods of connection have been shown for the purpose of illustrating that the route control codes for the different routes may be selected as desired from the complete route control code table, and that the various routes do not necessarily require particular codes.

It may also be noted that if the route relay I 2 were picked up in response to the operation of the entrance button 2NB andthe exit button IXB so asto actuate its polar contacts to left-hand positions, then the code No. 4 will be applied. The only diiference between code Nos. 3 and 4 is found in the character of the seventh impulse which is determined by the position of the polar Contact 265. Although this selection of codes for the two routes having opposite directions diifer only by the character of a single impulse, it is to be understood that codes may be selected which differ by the character of two or more impulses, if so desired by providing additional polar contacts on the route relay-I Z Also, the difference between codes selected for opposite directions in a route may be provided on any impulse or impulses desired, which has been illustrated more specically with respect to the route relay 4 2 which has its polar contact 261 provide the difference between the two codes for opposite directions for the route from signal 4 to signal 2 on the fifth impulse of the cycle.

It is believed that it will be readily understood by analogy to the description given in connection with the route relay I 2 how the` other route relays 4 6- and 4 2 provide for the transmission of their route control codes when the code determining relay ICD is picked up as previously described. However, it is believed that it will be expedient to point out the reason for the chain stitch'interlock between the contacts 268, 259 and 21B of route relay 4 2 with the contacts 21I,` 212 and 213 of the route relay 4 6.

VIt was mentioned above `that only one of the route relays 4 6 and'4 2 may be picked up at the same time, so that both ro'ute relays `may be associated with a single code determining group including relays ICH and ICD. Also, as these route relays 4 6 and 4 2 govern routes which are conflicting routes, the same code may be employed for putting both routes to stop, but as the picked up condition of either route relay is to transmit a code for clearing its corresponding route, the picking up of either relay must also prevent the transmitting of the stop code. Therefore, the code buses 25|, 252 and 253 are selectively connected to the buses 41 and 48.,

through back contacts of both of the route relays 4 6 and 4 2 so that the picking up of either route relay connects code buses 25|, 252 and 253 selectively to the buses 41 and 48 in accordance with the particular clearing route code of the'fgo route relay then picked up and disconnects the stop code connections which are in accordance With the code No.9 in the typical code table.

Transmission of emergency switch control code. The manual individual control of a track# switch is desirable under certain emergency conditions which arise in an interlocking plant, such as the operation of trackswitch back and forth when it fails to entirely complete an operating` stroke due to ice or lumps of coal or the like," and such as the setting up of the trackway for the passage of hand cars and the like although it is not desired to clear the signal for such a route. This manual control is provided in accordance with the present invention in such a LV'35 Way as to be'possible so long as the track switch is free to be operated, but when it is included in a route which is'cleared by the entrance-exit control, the operation of such switch by the emergency switch machine control lever SML isk effectively prevented.

Assuming that all of the routes are at stop, letlus consider the operation in response to the use of this emergency switch control lever SML.

tion closes contacts 214 and 215 to complete a circuit from (-l-), through the lower winding R of the relay Z, to while the operation of the lever SML'to its normal position closes contacts'216and211 to complete a circuit from ,lthrough the upper winding N of relay Z, to The energization of the reverse winding of the -relay Z actuates the polar contacts of this relay to left-hand positions and picks up its neutral contacts; while the energization of the normal i" winding N of the relay Z actuates its polar contacts to right-hand positions and picks up its neutral contacts. This'is because the windings N `and R are differentially connected. Therefore, if both of the windings N and R of the relay Z are? energized at the same time the magnetic flux produced to act upon the armature is substantially Zero because of the neutralizing effect of one winding upon the other. This feature of operation comes into effect in the event that a"Y route relay, such as route relay I 2, is picked up closing front contact 218 which applies energy to the normal winding N of the relay Z so that if the lever SML is operated at that timeI The operation of lever SML to-its reverse posi-'F145 4--2 is pickedup closing the Contact 282 to energize reverse winding Ref the relay Z if lever SML is operated'to its normal position to also energizethe normal winding N of the relay Z.y

In otherwords, if a route relay is picked up at the same time with the emergency lever SML in an operated position, the contacts of the relay operation of the lever SML to the normal or reverse positions 4correspondingly energizes the relay Z andconditions it to transmit a switch control! code, which is effected when the operatorI actuates the self-restoring starting button SB to pick up'the change storing relay 3CH, as previously'pointed out, for causing the initiation of `the system into a cycle of operation.

i 'I'he first three impulses of the code are determined in accordance with jumpers 233, 234 and.` f

235 to transmit the station code call y (-1-) as assigned in the typical code table. v From' the typical code table it will also be observed- .trol jumper in place of the extension of the code Abuses through the Z relay, but it .may be desirable to control' additional switches through the same. code determining group, that is, relays SCH and.3CD, and in order to be able to obtain the additional combinations, it is necessary to carry Vthe selections through any other relays Z .in a chain stitch fashion from the back contacts 219, 28D and 28| ofthe relay Z in a similar fashion as ,hasbeen provided in connection with con- 'A tacts'268, 269, `210, 21|, 212 and 213 for the route relays 4 2 and 4 6.

However, for the purpose of the present disclosure, the code buses 25|, 252 and 253 havefbeen shown respectively carried through front contacts 283, 284 and 285 of the relay 3CD over wires 28,6, 281 and 288 to the contacts 219,280 and 28| respectively. With the -relay Z pickedv up, the connections from contacts 219 and 280 provide that the fth and sixth impulses shall be negative while the seventh impulse is .positive if the relay Z is actuated to a normal position and is negative if the relay Z is actuated to a reverse position as determined by the polar contact 289.

When the switchl control code has been transmitted, the system of course restores `tofits nor- 4. v mal condition dropping the relays 3CD and 3CH,

as previously described. However, the relay Z will remain in the position to which it is actuated by the lever SML until this lever SML is restored'to its central normal position.

Field station reception of codes-Before' considering how the route control codes are received at the iield station, it is considered expedient to briefly point out the operation of the field station 'code receiving unit, although reference may be made to the above-mentioned applic'ation'YSer. No. 640,062, filed October 28, 1932 for a detailed )description of station selection and the like.

The rst impulse of a cycle of operation impressed upon the control and stepping linecircut including line'wires I9 and |2, is repeated v.by the line relay-F1 .so as to energize the repeating relay yFP1 through the mediumzof the polar contact |0| irrespective of the polarity of the impulse.` This rst impulse is alsosuciently long to pick -up the slow acting relay SA1, which remains picked up throughout the'operatingv cycle eitherby receiving momentary energzations through 'front contact' |01 of relay FP1 or from the polar con-` tact I0| of relay F1.

So long as the station is I capable of being selected or has. `been selected, n

the relay SO1.is picked up and the relay FP1 continues tov operate to repeat the impulses by the line relay F1, but when ther station relay SG1 :drops away, then the relay FP1 ceases operation.

The stepping relays V1 andhalf-step relay VP1 `are controlled by the relay FP1 ina manner'ex- 4plained in detail for the-'stepping bank ,inf the control oflice.

at the beginning of the'cycle of operation and is maintained selectively picked up dependent upon 1 the character of the iirst three impulses whichv rendering the jumper |29 effective to maintain the station selecting relay S01 picked vup through-- l `out the remainder of the cycle of operation until 'the last stepping relay LV1 back contact I3 y yThe station selecting relaySO1 yis picked up .'25

i 30 1 is picked up openingj Thus, the stepping relay bank.Y Voperatesv throughout the cycle andthe picked up condition of the station selecting relay S01 provides that the decoding relays NS and PS may. be positioned in accordance withy the character ofthe route control code impulses. All of the route conrelays are selectively picked up in `accordance with the vcharacter of the code impulses, only the pick-up circuits for the been shown in Fig. 5.

. More specifically, if the seventh impulse of the v cycle of operation is a positive (-1-) impulse, then the polar line relay F1I has its polar contacts operated to the right and the stepping relay 6V1 l having been picked up, a circuit is closed from through a circuit including front contact Ilof station selecting re1ay'SO1,y polar contact I4 of line relay F1 in `a right-hand position, front contact 290 of stepping relay 6V1, lower winding of decoding relay 1PS,`to When this relay 1PS is picked up, itis maintained picked up by a` stick circuit (see Fig. 6) closed from (-1-),

relays 1PS andlNS have Y,

through a circuit includingfront contact 29| of` station selecting relay SO.1,front contact 292 yof relay 1PS, upper winding .of relay 1PS,k to

This stick .circuit is maintained closed throughout the cycle of operation, butias the picking up of the last stepping relay LV1 causes the station selecting relay S01 to drop away, avfront contact 293 on the relay LV1 is provided to continue to energize the stick circuituntil such slow acting last stepping relay LV1 drops away. There is no interval of opening in the. stick circuittasf the relay LV1 picks up before the relay S01 drops away.

Infasimilar manner, if the seventh impulse is negative in character, a pick-up circuitis closed e for the decoding relay 1NS (see Fig. 5) from vthrougha circuit including-front contact ||8 of relay S01, polarcontact 4 of relay F1 in a lefthand position, front contact 294 ofstepping relay 6V1, lower winding of relay TNS, to When the ldecoding relay TNS` is picked up, it is main` tained stuck up throughout the cycle of operation by a stickY circuit similar to thatyprovided for the relay TPS, namely, a circuit closed from through a circuit including. front contact 29| of relay S01, front contact 2950i relay TNS, upper winding of relay TNS, to.().

Itwill be readily apparent that each of the decoding relays 4PS, EPS, PS and TPS are respectively connected to front contacts `IIE, 29S,

-29T and 290 of the .stepping relays shown in Fig. 5; while the decoding relays ANS, ENS, NS andYTNS are respectively connected to front contacts H9, 298, 299 and 294 of the stepping relays shown in Fig. 5.

It willfalso be apparent from Fig. 6 that each of `the-relays PS and NS have similar stick circuits controlled by the contacts 29| and 293 of the relays S01 and LV1 respectively. i

Reception of route control coda-Let us assume that the operator has operated the entrance button INB and the exit button ZXB picking up the route relay |-2" and therefore causing the transmission of the code No. 3 in the ltypical code table, The first three impulses in this code select the station, as above pointed out, causing'the station selecting relay S01 to be maintained up only at this particular field station for the cycle of operation under consideration, and during the last four impulses of which the relays APS, 5PS, BNS and TPS are respectively picked vup and maintained picked up until the end of the cycle of operation and the dropping of the last stepping relay LV1, at which time the code set up by these relays is executed to the proper route relays for controlling the trac controlling devices.

With this code set up upon the decoding relays, an execution circuit is closed during the time that the last stepping relays LV1 is picked up subsequent to the dropping of the slow acting relay SA1. It will be apparent from Fig. 5 that this time period will be equal to the dropping away time of the relay LV1. This execution circuit for the particular code assumed to be set up is closed from through a circuit including back contact 300 of relay SA1, front contact 30| of relay LV1, back contact 302 of relay ANS, back contact 303 of relay 5NS, back contact 300 of relay SPS, back contact 305 of relay TNS, front contact 306 of relay APS, front contact 30T of relay EPS, front contact 308 of relay ENS, iront contact 309 of relay TPS, wire 3I0, back contact 3|| of routeV relay 2-lR, lower winding `of route relay |-2R, to`(-).

As soon as the route relay |-2R picks upyit `is maintained picked up by a stick circuit closed from through a circuit including back contact 3|2 of stop route relay I-ZS, front contact 3|3 of route relay l-2R, upper winding of route relay |-2R, to

Thus, at the end of the execution period and the opening of the execution circuit just pointed out, all of the decoding relays PS and NS drop away to their normal positions, but the route relay |-2R remains picked up due to its stick circuit so as to set up its route and clear the signal for such route.

The picking up of the route relay |-2R closes anenergizing circuit for the normal switch controlling relay WN from through a circuit including front contact 3|ll of routerelay |-2R, bus' wire 345, lower winding of relay WN, to

`When the relay WN is picked up,vit is maintained maintains the relay WN in a picked up condi- I tion until the reverse switch control relay WR is picked up for some other route in response to a route relay, such as relay 42R, or in response to the reception of an emergencyswitch control code as will be explained hereinafter.

With the relay WN picked up, the normal switch machine control circuit is closed` from (-I-),'through a circuit including front contact 3|T of track relay |5T, front contact 3i8 of track relay IlIT, front contact 3I9 of lock relay L, back contact 320 of relay WR, front contact 32| of re lay WN, through the switch machine SM, to 'Ihis causes the normal operation of the switch machine SM and the operation of the crossover TS to normal positions which is repeated by `the relay WP.

-With the crossover TS in a normal position, either when it has been in such position initially or when it has just operated to such position, a circuit is closed for energizing thesignal con trolling relay IG from through a circuit including front contact 322 of relay WP, polar contact 323 of relay WP in a left-hand normal position, front contact 324' of route relay |-2R, winding of relay IG, to

The picking up of the contacts of the relay IG changes the indication of the signal I from stop to clear so that a train may proceed over the route from signal I to signal 2 on to the end of such route. While the signal I is cleared, the locking relay L is deenergized in accordance with the usual practices for locking a route so as to pre- Vent the `operation ofthe switch machine during such a clearing condition of the route. Also,ithe passage of the train over the track section MT, deenergizes the track relay MT opening front contact 3|8 so as to further insure the continued locking of the switch machine SM, although the signal is either automatically or manually put to stop.

In this connection, it is to be understood that the signal I may be entirely under manual control as shown in the present disclosure, or it may be a semi-automatic signal, that is, a signalautomatically put to stop by the passage of a train. It is also to be understood that this signal I and the other signals of the disclosure may be of the stick signal type, that is, put to stop by the passage of a train, and incapble of being cleared until both a stop and a clear control has again been received. This may be accomplished in any of the usual ways provided in signalling practice. But for the purpose of simplicity in the present disclosure, manual control onlyr is provided for putting the signals to stop.

More specifically, the signal I is returned to its stop condition by the transmission over the system of the stop code in the response tothe return of the route relay I-2 to a deenergized condition, as previously pointed out.

This stop route code No. 13 sets up the code (-l) on the decoding relays PS and NS so that an execution circuit at the end of the iso layNS, front contact 330 of relay yGPS ,iront contact 33| of'relay'lPS, wire 332,v windings of stop route relay |-2S, to

The stop route relay |--2S, and alsoallI other `stop route relays, such as relay 4-6S, are only energized during the execution period, but this period of energization is suilicient for picking the stop route relay up and it remains up for asuiiicient period of time to drop out any of the route vrelays with which it is associated. For example,

the stop route relay |-2S controls the route relay |-2Rv and opens its stick circuit-at back contact 3|2 and allows this route relay I-ZR-to `drop away putting to stop the signal by deenergizing relay IG upon the opening of frontcon-y However, it is considered well to note that the f picking up of the route relay 4 -2R for example,

closes front contact 333 which will energize the v lower winding of the relay WR through an obvious circuit. The picking up of the relay WR opens contact 3|6 to deenergize the stick circuit for the relay WN and closes its own stick circuit from (-f) through a circuit including front contact 3|6, yback Contact 3|5 of relay WN, upper winding of relay WR, to The closure of Iiront contact 320 of relay WR and back contact 32| of relay WN causes the reverse operating circuit of the switch machine SM, which will cause the crossover TS to operate to a reverse position which is repeated by the switch position repeating-relay WP.

The front contact 334 of route relay 4-2R causes the energization of the signal clearing relay 5G for changing the indication of signal 5 from clear to stop, but this energizing circuit for the relay 5G requires the switch position repeating relay WP to indicate that the crossover TS is in a reverse position before this circuit vcan be energized.

. In brief, it will then be understood from this operation, that each route control code not only causes the operation of the switch (or switches) in the associated route and the clearing of. the signal Afor that route, but requires that the track switch' (or switches) controlled thereby shall be in proper positions and have responded to their controls properly before a signal can be cleared for that route. There is a route relay such as |-2R, 2-|R, 4-6R, etc. foreach of the routes. Also, each route may include a single track switch Ior a plurality of track switches and Crossovers although the present disclosure of Fig. 7 merely shows a single crossover. a plurality of track switches are,employed,.the particular routerelay picked up controls all of ithe WN or WR relays for all of the track switches involved in the route which that route relay governs and the signal selecting circuits for controlling the signal relays G require that all of the v track switches be in their proper operated posiroute.

tionsbefore the proper relay G can respond to the energized condition of the route relay for that Reception o-f emercencyswitch control code.- As above described, vand with reference to the Ytypical code table, it will be seen that code Nos.

In such cases wherev 7 and 8 are employed for the emergency operation of the switch machine SM in response to the manualy control of the emergency switch control lever SML.

Let us assume that the reverse switch operating code No. '7 is transmitted and stored in the decoding relays PS and NS. rThis will setup an executing circuit at the end of the cycle from through a circuit including back contact 300 of relay SAl, front contact 30| of relay LV1, back Contact 302 ofr relay'4NS,V back contact 326 of relay 5PS, back contact 304 of relay SPS, back contact 305 of relay INS, front contact 335 of relay llPS, front contactl 336 of relay 5NS, front contact 331 of relay GNS, front contact 338 of relay 1PS,.wire 339, lower winding of relay WR,

to This circuit energizes the relay WR causing the relay WN to be deenergized and close the stick circuitfor the relay WR previously pointed out. This will eiTect the operation of the switch machine SM providing it is unlocked and no signal hasvbeen cleared. If the relay .WN,

for example, is energized vby reason-of the closed condition of front contact 3|4 of route relay |-2R previously picked up for'clearing a route,-

then the relay WR will be only momentarily energized during the execution period and will again drop away as the relay` WN `is permanently held by th-e energization ofrits lower winding so long as the route relay y|--2Rl is` picked up. Itwll be apparent that the same condition exists if any other of the route relays were picked up requiring the crossover TS to be in a normal position.

Let us assume that the normal switch'operatf ing code No. 8 is transmitted and stored in the decoding relays PS and NS, this will set up ank executing circuit at the end of they cycle from (-1-), through a circuit including back contact 300 of relay SA1, front contact 30| of `relay LV1, back contact 302 of relay 4NS, back contact326 of relay 5PS, back contact 304` of relay GPS, back Contact 340 of relay '|PS,.front contact 34| of relay 4PS, front contact 342 of relay 5NS, front contact 343 of relay GNS, front contact 344 of relay HNS, wire 345, lower winding of yrelay WN, to This vcircuit energizes the relay WN causing the stick circuit for the relay WR to be broken and close its own stick circuit previously pointed out, providing of course that no route relay is holding the relay WR energized such as, for example, th-e closed condition of rontcontact 333 of the route'relay 4-2R. The control ofthe .relay WN under such circumstances will be similar to that pointed out in connection with the relay WR.

1. In a centralized trac controlling system for railroads, a track layout containing a plurality of track switches operable to normal and reverse positions to form a plurality of routes, vl

signals for governing traic yover said routes, a

code type communication system connecting a control oflice with said track layout, control buttons in said control ofce designating the ends of said routesv through said track layout, means responsive to the joint operation of the control 55 I Having thus described a centralized traflc` 

